Combination coil and resistor shield



Jan. 16, 1945.- A. HALLETT I COMBINATION COIL AND RESISTOR SHIELD 7 t 52 m v a P fi 2 wag W n /w 1% U! b A. 7/ 7 o W 7 4 T W a w w w W W O v aW a 2 ATTORNEYS.

Patented Jan. 16, 1945 COMBINATION con. AND RESISTOR SHIELD AlfredHallett,-Los Angeles, Calif., assignor to Hallett Manufacturing Company,Inglewood,

Califl, a copartnership I Application 'June15, 1942, 12 Claims. (01.123-1455 This invention relates to the shielding and protection ofelectrical systems for internal combustion engines. 1

Free electrical radiations from ignition systems of internal combustionengines used in proximity to radio receiving apparatus are picked up insuch apparatus and interfere with reception; This is a serious factor inthe operation of airplanes, motorboats, submarines, military landvehicles, and all other types of mobile transportation, as wellasin-stationary installations, em;-

ploying radio equipment.

Various forms of shielding have been employed for thepurpose' ofgroundingelectrical radiai tions, but until my present invention I amaware of -no combination coil and resistor'shield which will serve thedual purpose of protecting the terminals of the coil and resistor fromadverse effect of the elements and at the same time electrically shieldthe combinedunitto prevent undesirable radiations. f v

When the elements, of an ignition-system, such, for example as the coiland resistor, are exposed to'weather or adverse operating conditions,moisture, water, oil, and gaS may be deposited on the coil or theresistor unless protected by moistureproof and water-proof enclosures.Inasmuch as cables must lead to various parts of the combination coilvand resistor unit, such protective! means should include the regionswhere the caa bles enter the protective housing.

It is therefore anobject of my invention to.

provide an electrical shielding fora combination coil and resistor unitwhich combinesthe func-u tion of physical protection to the elements ofthe unit, against weather and-other adverse operating conditions whichnormally contribute to failure of the unit, deterioration of insulation,

connections, etc. f

It is a further and more specific-object of my Serial No. 447,078

ple' the coil known Scintilla. v

This applicationis a continuation in part of my copendingapplicationserial No. 427,621, filed,

under the trade name of January 21, 1942, for'Shielding for electricalsystems.

These and other objects of *my invention will be made more apparent fromaconsideration of the full description and drawing.

In the drawing: Y 1 i Figure 1 is a vertical view partly in section ofmy shielding applied to an ignition coil and re sistor unit. 3

Figure 2 isa cross-sectional'view of the same taken on the line 2--2 ofFigure 1.

My combination coil and resistor shield assembly comprises generally acoil lfl, resistor H, and a shield housing 12 of substantially highconductive properties,

The coil illustrated is provided with a metallic casing I 3 having heatradiating fins I4, mounting brackets l5 for attaching the coil to theframe or motor, not illustrated, and a brass ring Iii .encircling theupper part of the coil. The coil illustrated and described 'is standardand commoniy known as the -Scinti1lacoil.

For use in conjunction with this coil I provide the resistor H. whichprimarily includes a coil invention to provide'a metallic shielding foran I individual coil and resistor unit, wherein the coil i may embody ametallic casing partially enclosing the shell around the winding's,asfor examof resistance wire |1 attached to low tension connections I8 andIlia, the latter of which are mounted upon an insulating block [9. Theresistance element I! is preferably embedded in a casing in tubular formof investment cement 20 or any other-kind of material which is anonconductor when dry, is preferably hard and has heat radiatingproperties.

My metallic shield housing I2 is of novel construction and comprisesthree primary parts 2|, 22, and 123. The part 2| and the part 22cooperate to enclose and clamp upon the upper part of the coil, and thepart 2| in addition provides an auxiliary compartment for the resistorunit. The part 23 functions as a cover. In design,.the parts 2| and 22are in effect one, but are split at 24 to enable their installation uponthe coil, and are secured together on'the coil by means of cap screws25. The parts 2| and 22 are preferably formed with an annular channel 26serving to engage and clamp upon the brass ring l6 of the coil, and areprovided with extensions 21 which engage the upper edge of the metalliccasing I3. l

As before stated, the part 2| is formed wit a compartment or pocket30'into which the re sistor ll may be inserted, the resister being se--terial is usually considered an artificial stone, the

basis of which is usually magnesium oxychloride. The resistor isconnected to the coil circuit in conventional manner. 1

Heat radiating fins 34 may be formed on the wall of the resistorcompartment.

I provide low tension terminals 35 entering the housing at the side, anda high tension, terminal 36 entering the housing through the cover.

In the case of the terminals it is desired to efiect a water-proof,moisture-proof and airtight seal where the cables enter the housing andalso to assure a complete electrical contact between the metal shieldingof the cables and the housing. Any suitable terminals which fulfill suchrequirements may be employed. However, I prefer terminals of the generalcharacter illustrated in my aforesaid copending application Serial427,621.

The low tension terminal 35 comprises generally a metal collar 3'!threaded into an opening 0 3,8 in the housing. This collar is formedwith an internal annular ledge 39. Snugly fittingwithin the collar is aninsulator 40 having a shoulder 4| seating on the ledge 39 and beingformed also with a beveled seat 42 at the upper end., Resting U in thisseat is a frusto conical insulating gland 43 preferably of soft rubber.A metal bushing 44 having a vertical cylindrical portion through whichthe cable 45 extends and a. flat disc at thelower end is seated on theupper face of the gland- 4-3.. It. is preferable that the cylindricalportion of the bushing be inserted between the metal cable shielding 46;and the insulation 45a of the cable. The lower end of the shieldingshould be spread out over the disc portion of the bushing, and a ferrule4:1: having, a flange at its. lower end rests upon the outturnedshielding. and serves to. center the cable. A threaded cap 48 screws.down on the collar 3-!- to secure the various parts; tightly in place.

The shielding on the cables illustrated here is in the form of a wovenmetal sheathing but a tubular enclosure or other equivalent shieldingfor. the cable may be, employed.

The high tension terminal 36 involves certain modifications of the lowtension terminal. It comprises generally a collar 31a. similar to thecollar 31 and threadedinto an opening 381:. This collar is formed with adownward extension 31?). An insulator 400:. seats onthe internal ledgeof the collar. In the high tension terminal it is preferred to space theshank 50 of the insulator from the major portionof the collar..

The cable 4.5a passes through a gland 43a and the insulator, the cableinsulation 46aending at a, shoulder 5i formed by the reduced end 52 ofthe insulator. A metal bushing 44a which may be crimped upon-the cableshielding 41a or be otherwise secured upon it has a flanged portionresting upon the upper face of the gland 43a and is forced down by a cap48a threaded upon the upper extension of the collar 3.1a;

The lower end of the cable wire 53 passes through the bore of a terminalelement 54 and is I preferably soldered thereto. This element 54 has anupper shank 56 which fits snugly in the reduced lower end 52 of theinsulator and a flange 51 which bears against the lower extremity of theinsulator. A spring 58 is attached to the terminal element 54 and makespressural contact with a conventional post (not illustrated) of thesecondary winding in the coil within a hollow pedestal 60.

Both low tension and high tension terminals are locked securely to thehousing, insuring an efficient and satisfactory connection with the coiland providing a moisture-proof and water-proof entry of the cable intothe housing as well as a complete grounding of the metal cable shieldingI r tothe housing.

Thus I have achieved an ignition coil and resistor unit completelyenclosed in a structural sense as a protection against water, oil, anddirt and completely shielded electrically by a housing which has highconductive properties and which is positively connected with the cableshielding serving to dissipate into the ground all electrical radiationsoccurring in the unit. I have achieved an improved radiation of heatfrom the resistor, protection of the resistor elements and theconnections of the resistor with the coil, and attained' a simplicity inconnecting up the resistor and coil, as well as providing terminals forthe leads of these two electrical elements; and have formed the commonhousing for the two elements of three pieces as described enabling themto be quickly and readily assembled on a standard type of coil of thecharacter shown.

Although I. have herein shown and described my invention in what I'haveconceived to be the most practical and, preferred embodiment, it isrecognized that departures may be made therefrom within the scope of myinvention, which is not to be limited to the details disclosed hereinbut is to be accorded the full scope of the claims so as .to embrace anyand, all equivalent structures.

. Having described my invention, what. I claim as new and] desire tosecure by Letters Patent is:

1. In combinationwith a coil. provided with a metallic casing anda'shouldered ring. secured on the coil above said, casing: a shield ofhigh conductive properties comprising a split housing formed with ashouldered recess. adapted to engage and be clamped. upon said ring withsaid housing seating upon the upper end of said casing, a compartment insaid housing, for a resistor, andv cable terminals entering said housingand establishing an electrical connection between metal shielding onsaid cables and the said housing.

2. In combination: a shield housing. of high conductive propertiescomprising a resistor compartment, a resistance element in saidcompartment, insulating heat radiating material packed in saidcompartment around said resistance element, cable terminals leading intosaid housing and establishing an-electrical connection between metalshielding-on said cables and the said housing, and means. adapted toclamp said housing over the upper portion of a coil contiguous toametallic casing enclosing the lower portion of said coil whereby thecoil and resistance element are entirely enclosed in an-electricalshield.

3. In combination: a. shield housing: of high conductive properties,comprising aresistor compartment, aresistance element in said:compartment, insulating heat, radiating material packed in saidcompartment: around. said, resistance element, cable terminals leadinginto said housing -coil whereby the coil and resistance element areentirely enclosed in an electrical shield, and means to obtain access tothe upper end of said coil and to said resistance element for establishing interconnections of coil and resistance element.

for establishing interconnections of coil and resistance element.

4. A combination as described in claim 2 in Y which the housing embodiesa shelf adjacent the resistor compartment, and an insulating blockmounted upon the shelf adapted" to support the resistance element.

5. In combination: a shield housing of high conductive propertiescomprising a resistor com-' partment, a resistance element insaidcompartment, insulating heat radiating material packed in saidcompartment around said resistance element, moisture-proof andwater-proof cable terminals leading into said housing and establishingan electrical connection between metal shielding on said cables and thesaid housing, and

means adapted to clamp said housing over the upper portion of a coilcontiguous to a metallic casing enclosing the lower portion of said coilwhereby the coil and resistance elementare en- I tirely enclosed in anelectrical shield.

6. In combination: a shield housing of high conductive propertiescomprising a resistor compartment, a resistance element embedded insaidcompartment, and means adapted to clamp said housing over the upperportion of a coil contiguous to a metallic casing enclosing the lowerportion of said coil whereby the coil and resistance element areentirely enclosed in an electrical shield, said coil and resistanceelement being spaced apart for maximum heat dissipation.

7. In combination: a shield housing of high partment, a resistanceelement cementitiously embedded in said compartment, meansadapted tobeing spaced apart for maximum heat dissipation, and means to obtainaccess to the upper end of said coil and to said resistance'element 7conductive properties comprising a resistor com- 8. In combination: ashield housing of high conductive properties comprising a resistorcompartment, a resistance element in said compartment, and means adaptedto clamp said housing over the upper portion of a coil contiguous to ametallic casing enclosing the lower portion of said coil whereby thecoil and resistance element are entirely enclosed in an electricalshield,

said housing embodying a shelf adjacent the resistor compartment, and aninsulating block mounted upon the shelf adapted to support theresistance element.

9. A combination coil and resistor shield comprising a housing of highconductive properties, said housing comprising two primary complementaryparts adapted for clamping on an induction coil and formed with anannular recess for engaging a ring on said coil, and one of said primaryparts including a receptacle for a resistor. I

10. A combination coil and resistor shield comprising a housing of highconductive properties,

said housing comprising two primary complementary parts adapted forclamping together upon an induction coil, and one of said primary partsincluding a resistor compartment spaced radially and laterally from saidcoil, for maximum heat dissipation. v

11; A combination coil and resistor shield comprising a housing of highconductive properties, said housing comprising two primary complementaryparts adapted for clamping upon the upper end of an induction coil, oneof said primary parts including a resistor compartment spaced radiallyfrom said coil, and a cover removably secured upon said complementaryparts above the terminal end of said coil and above said resistorcompartment, and having high tension cable terminal means providingelectrical connection with cable shielding.

12. A combination coil and resistor shield comprising a housing of highconductive properties, said housing comprising two primary complementaryparts adapted for clamping on an induction coil and formed with anannular recess for'engaging a shouldered ring on said coil, and

one of said primary parts having a resistor receptacle spaced from saidcoil and a resistor.

sealed in said receptacle.

ALFRED HAILETT.

